The technical field of this disclosure is lighting control, particularly, control of automatic cycling for HID lamps.
High Intensity Discharge (HID) lamps, such as mercury vapor, metal halide, high-pressure sodium and low-pressure sodium light sources, are used for a variety of lighting tasks. It is known that many HID lamps need to be turned off at least once per week to maintain proper operation. This requirement is listed on the specifications for many lamps, in particular, for metal halide lamps. HID lamp manufacturers instruct users to cycle HID lamps off and on every 168 hours or so (about once per week).
Many applications involve operation of HID lamps for long times without turning them off, however. It is up to the end user of the lamp to turn off the HID lamps at least once per week, either manually or through an automatic building control system external to the lighting fixture. Through either ignorance or negligence, this requirement may not always be met. In some applications, it may not be possible or desirable to turn off all the lights in a given area at once. This can result in improper operation of the lighting system and the lamps may be left on continuously.
If lamps are not turned off regularly, they may fail catastrophically with rupture of the arc tube. The rupture can damage the lighting fixture and its surroundings, and may even pose a hazard to personnel if the lamp is operated in an unprotected fixture.
It would be desirable to have an automatic cycling control for HID lamps that would overcome the above disadvantages.
One aspect of the present invention provides automatic cycling control for HID lamps.
Another aspect of the present invention provides automatic cycling control for HID lamps integral to the HID lamp system.
Another aspect of the present invention provides automatic cycling control for HID lamps with varied timing to stagger cycling in groups of HID lamps.
Another aspect of the present invention provides automatic cycling control for HID lamps that avoids unnecessary cycling if cycling has already occurred.
The foregoing and other features and advantages of the invention will become further apparent from the following detailed description of the presently preferred embodiments, read in conjunction with the accompanying drawings. The detailed description and drawings are merely illustrative of the invention, rather than limiting the scope of the invention being defined by the appended claims and equivalents thereof.